Emergency personnel, such as firemen, are often required to use SCBA's when working around a toxic atmosphere. Whenever emergency workers must use SCBA's, their effectiveness is curtailed because of the limited supply of air that is provided in a SCBA. When a worker's air supply becomes depleted, he must leave the scene of the emergency to replace the empty tank. Given this limitation, workers waste valuable time leaving the scene to refill their air tanks.
Similarly any time that a worker uses an SCBA, he becomes dependent on his air supply. If the worker becomes trapped or injured and can not leave the scene on his own, he will suffocate when his air supply is exhausted. To save the trapped worker's life, the worker can share the air supply of another worker using an SCBA. The sharing of air supplies is called "buddy breathing".
The concept of buddy breathing is a relatively old idea in which two persons using SCBA's share a single SCBA's air supply to provide mutual safety, when one user faces air depletion during a hazardous situation. The air is normally shared by taking low pressure air directly from the mask or regulator of the donor SCBA. The concept of sharing an air supply by taking low pressure air directly from the regulator has been disclosed in numerous U.S. patents including: Kirby, U.S. Pat. No. 4,111,342; Mattingly, U.S. Pat. No. 4,392,490; and Gray, U.S. Pat. No. 4,449,524.
There are problems inherent in such methods of sharing air. One problem is that both men are joined together throughout the procedure. When the men are attached together, it is often impossible to exit a building through small escape paths such as windows or doors. It is also possible that a connecting air tube can become damaged or entangled. Further, this arrangement necessitates that both men leave the emergency scene at the same time so that the man with the exhausted air supply can reach a safe atmosphere. This means that an additional worker is temporarily deterred from fighting the emergency.
Another situation in which this arrangement presents a problem is when one worker becomes trapped. In order for another man to share his air supply, he must remain with the trapped worker until help arrives, thereby endangering his own life as well.